Recovery and utilization of waste engine heat



Sept.v 16, 1941'. R. D. WILLIAMS RECOVERY A ND UTILIZATION- OF WASTE ENGINE HEAT -Original Filed April 4, 1938 2 Sheets-Sheet l SQN Illlhi Il N www L mmf/ n.4 www Sept. 15, 19.41 RQ D.. WILLIAMS 2,256,303

l RECOVERY AND UTILIZATION 0F WASTE ENGINE HEAT Original Filed April 4, 1938 2 Sheets-Sheet y2 FIGB. IIfaI o o oOoQOooo ooooooooo o' ooo oooooocfooo INVENTOR. Roe ERT D. WILLIAMS AISTORNEY.

Patented sept. '16, 1941 RECOVERY AND UTILIZATION OF WASTE ENGINE HEAT I' Robert D. Williams,.Memphls, Tenn., assignor to Fairbanks, Morse & Co., Chicago, Ill., a corporation of Illinois original application April 4, 193s, serial No.

Divided and this application December 7, 1939, Serial No. 307,956

2 Claims.

'I'his invention relates to improvements in the recovery and utilization of waste vengine heat, and more particularly to an improved -air heater and heat exchanger apparatus having particular utility in systems for thermally conditioning certain solid materials either prior to or while in process of mechanical treatment. The invention is particularly identified with an improved utilization of heat from the prime mover, such as an internal combustion engine, employed as a source of mechanical energy for processing such materials.

4The present application is a division of my a'pplication for Letters Patent on Utilization of waste engine heat, led April 4, 1938, and bearing Serial No. 199,821.

In many of the arts and industries it is advantageous to -treat a material as by heating or drying, incident to the mechanical processing, cleansing, finishing, calendering, or otherwise mechanically valtering the dry material. An example is found in the ginning of cotton, wherein it has been determined that removal of trash from the seed cotton is relatively easier when the cotton and foreign matter are both comparatively dry. It is accordingly to the attainment of a more eiiicient drying process and a reduction of the expense thereof, that the present invention is primarily directed.

Another object of the invention, more particularly stated, consi-sts in the utilization of heat, for the purpose of effecting the drying of` cotton incident to ginning thereof, from either orl both the exhaust and cooling water of an internal combustion engine utilized as the prime mover for the cotton gin. Bythe utilization of the irnprovedappa-ratus for the purpose, the overall efliciency of the entire ginning plant, and the eiliriency of the engine, are obviously considerably enhanced.

Incident to the foregoing it is within the purview of the present invention and is stated as an object thereof. to provide for means utilizing the waste engine heat at least in substantial proportion, for maintaining a stream of air for cotton drying, at a substantially 'constant temperature.

Yet another object of the invention is attained in a series of heat exchange devices which are correlated in design and functionally unied by their connection into a common hot air supplyl system, the units being supplied with heat from an internal combustion engine or the like, and this engine being employed as a source of mechanical power for ginning the cotton while subject to thermal treatment, as by a warm air stream conducted through a duct system.

Still another object of the invention is attained in a device for some or all of the purposes aforesaid, and which may be easily utilized for the incidental purpose of Ventilating the power plant enclosure and gin-enclosing structures, or a common housing therefor.

The foregoing and numerous other objects will appear from the following detailed description of a presently preferred embodiment of thev invention, when considered in connection with the accompanying drawings, in which: 4

Fig. 1 is a top or plan view, partly diagrammatic in nature, of the various elements in an engine waste-heat recovery system, utilized in combination with a cotton ginning plant powered by an internal combustion engine; Fig. 2 is a vertical longitudinal section of an assembly embodying as a unitary structure, a combined radiator, exhaust-heat exchanger and air furnace, the

plane of this section being indicated by line 2-2 of Fig. 1; Fig. 3 is a staggered transverse Vertical section through a portion of the device of Fig. 2, and as taken along line 3-3 of Fig. 1, and Fig. 4

is a broken horizontal section as viewed along line 6 4. of the device shown by Fig, 2.

Referring now by characters of reference to the drawings, there is selected for exemplication of the invention, a cotton gin I0 which may be of any suitable or known type, and which is not illustrated in detail since the ginning equipment per se forms no part of the present invention. It

is however contemplated that the present invention may be applied not only to the drying of seedcotton prior to its actual mechanical treatment in the gin, but also may be utilized as a source of heated air for use in air-blast gins wherein a stream of air under substantial velocity is directed to one or more, usually a plurality, of air-blast nozzles serving continuously to force streams of air substantially across the periphery of the gin saws. This specific mode of utilization of an air-blast in connection with a rapidly rotating` gin saw, may be, for example, such as disclosed in U. S. Patent No. 1,827,183 issued October 13, 1931, to C. A. Bennett. It will be understood for purposes of present description that the enclosure I il contains' suitable air-blast ginning equipment, with or without equipment suitable for pre-drying the cotton, i. e., thermally conditioning it prior to the time when the seed cotton is actually exposed to the gin saws and air-blast. A power supply shaft ll for the gin is shown in' Fig. 1 as actuated by a power pulley l2 driven..

as by a belt i3, from ,pulley il secured to an engine drive shaft il; the latter is conveniently in-' stalled as a countershaft, from which may also be driven several of the power-requiring accessories incident to the present process and system.

An engine 2l may be of Diesel type or may consist of some other suitable form of internal combustion engine of the power rating necessary to care for the power demands of the gin Il. The engine may consist of a single cylinder engine, or of a multi-cylinder engine, as diagrammatically represented. It is, however, preferably water.

cooled, the jacket structure being indicated gen-- erally at 2l provided with a -water circulating pump (not shown), and Jacket discharge piping 22 which leads to a cooling water radiator 21, the water being directed therefrom as by return piping 24, leading to the cylinder block and jacket of the engine.

-It is a preference in assembling the parts of the system, to provide the engine with an enclosing hood 30. This may be conveniently fabricated of steel sheet, and if desired, lined with a thermal insulating material 3| which serves the purpose of conservation of radiated heat, and in some measure as a deadening material for soundproofing purposes. An air inlet to the hood is shown at 32, and may have its entrance port at some desired point in the gin building or power plant structure, whereby to serve as may be desired, for ventilation purposes. An air outlet throat is provided, to cause a convergence of the air stream after passing over the engine. The air is directed as indicated by the arrows in Fig. 1, across the engine 2l, thence into the outlet throat of the hood. In the course of the air travel through the enlarged portion of the hood 30, the air stream will obviously be raised somewhat in temperature due to the effect of direct external radiation of the engine Jacket. If, as is much less usual, an air-cooled engine be employed, the radiator 23 and jacket 2l would of course be omitted, in which case the direct engine radiation into the incoming air stream would obviously be at a much higher value.

The radiator 23 may be of any suitable or usual type, either of tubular form, of cellular type, or of tube and fln type. the particular form oi' the radiator not being material, except that its design should be such as to minimize resistance to the air stream passing therethrough, via the duct elements later to be described. It will have appeared as obvious that the air stream is still further raised in temperature by direct heating effect of the radiator on the air as it is impelled across the hot surfaces of the tubes or cells. It will 'further have appearedthat when utilizing waste jacket heat from the engine, the radiator 23 being of a design, surface area and capacity to accommodate it to the air duct system herein after described, nevertheless the provision of such radiator is in lieu of the usual separate engine radiator.

The air stream in proceeding through the throat 35 converges into a duct 35, thence into the eye or inlet portion of a volute 31 of an air displacement device, such as a fan, blower or the like, indicated at lll. The exact form of air displacement device is not material to the invention, but a fan or blower of centrifugal type has been found economical and practical for the purpose noted. The outlet from the fan or blower l0 is connected into a duct section Il, thence through the radiator 23, and thence into the inlet air port hereinafter described, of a combined exhaust heat exchanger and air furnace unit, indicated generally at 42 (Fig. l), the detail of structure of a suitable form of exchanger and furnace unit more clearly appearing in Figs. 2, 3 and 4, and laterherein described more fully.

It is my preference that, for space economy and economy in length of duct, the radiator 23 be formed as a part of, or be supported by the shell of the unit I2. Such a support is arranged by flanged bracket elements 23A, which may be located within or exteriorly of the adjacent portion of duct Il, the brackets being in turn carried by the shell of the exchanger-heater unit l2.

As will later appear, the air stream from duct 4I, after traversing the radiator, passes through the exhaust heat exchanger, thence through the air furnace, whether or not the latter is operating, and from the outlet or delivery port of the air furnace, into a duct 50 and into the gin enclosure I0, wherein there are provided the requisite numbero'f branches for supply of the air blast nozzles of the gin, adjacent the gin saws, the latter structure not being illustrated. If necessary to care for the accumulation of air and slight increase in air pressure which might otherwise result in the gin structure i0, there is provided a discharge line orduct 5|, leading to atmosphere as through a window of the enclosure about the power plant or the gin.

It has been found convenient to utilize the countershaft I5 asa drive for the fan or blower 40, as through a drive pulley 52, belt 53, driven pulley 54 and fan drive shaft 55. It has also been found convenient to utilize for purposes of external combustion, when necessary to augment the heat derived from the engine and radiator radiation, as augmented by the exhaust heat exchanged into the air circuit in the unit 42, an oil burner which may be of a gun type or any other suitable form, advantageously utilizing the same type of fuel as that employed in engine 20, in case the latter is of Diesel type. The oil burner 80 incorporates therein the usual blower equipment which may be power-driven by a pulley 3|,belt 52 and pulley 63 (Fig. l)

Proceeding now to a description of the combined radiator, exhaust heat exchanger and air furnace unit, the engine 20 is shown as provided with oppositely disposed manifolds and $6, communicating respectively with exhaust pipes 51 and 58 both connected through a common pipe section, to exhaust gas inlet-port 10 of the heat exchanger unit. The exhaust gas inlet port is identified with the inlet connection, and leads into the upper portion of the shell 15 about the exhaust heat exchanger, the location of the connection 10 best appearing in Fig. 3. The exhaust entrance connection leads into the upper chamber 18, defined as by a flue or tube sheet 11 and the upper end of.the shell. A similarlower flue sheet 18 spans the wall of the exchanger shell slightly. above the bottom thereof and forms a chamber 19 in the lower portion of the shell. It will appear from Figs. 2 and 3 particularly, that the hot exhaust gases entering the port and connection 10, pass thence into the chamber 16. thence downwardly through certain of the plurality of parallel Vertical spaced tubes in the exchanger,

thence into the lower chamber 19, thence upwardly and outwardly through other of the tubes assembly of the exchanger in both a downward direction and an upward direction.

The air circuit through theE exchanger is provided by an inlet port 86 at the terminus of the duct just beyond the radiator, and extends throughout the intermediate space 87 in the shell of the exchanger in such manner that the air circulates closely about the tubes, and after being substantially heated by radiation from the exhausty gases, makes its exit into the air circuit of the air furnace, the latter portion of the unit being indicated generally at 90, to distinguish-it from the exhaust heat exchanger portion of the unit, indicated generally at 9|. i I

The furnace 90, as will appear from Figs. 2 and 4, is by preference, constructed as a companion unit to the exhaust heat exchanger. Each of the structures 90 and 9| is preferably of vertical tubular type as shown, each of rectangular transverse section (Fig. 4) and the units are assembled inV back-to-back relation. This arrangement facilitates removalv of either unit without structural disturbance of the other, as for repairs, replacement or service attention. In the event of the removal of either unit for such purpose, the open side remaining as a result of the disassembly, may be temporarily closed as by a flat metal sheet |0|, directly into a transfer or distribution chamber |01, discharging into the duct 50, thence into the gin enclosure I0 or by way of suitable branches (not shown) to the air blast nozzles adjacent thereasons of economy, obviously the first unit to of suitable gauge (not shown), bolted in place as a closure on the remaining unit. Temporary connections may be eiected, in such event, in an obvious manner. It may be noted as a preference that a single base structure 95 is provided for the assembly of units 90-9 and that such base structure is itself formed as a rigid unit common to the exchanger-furnace assembly. This conduces to structural stability, and the contiguous assembly of the units 23, 90 and 9|, provided for by the radiator location, and by companion flanges 96 and bolts 91, assures a minimum length' of travel of the hot air stream between the radiator and exchanger, also between the exchanger and furnace, minimizes heat loss between the several units, minimizes length of duct required, besides assuring compactness of assembly. This latter point is of advantage inthe event of installation of the present heat conservation system in existing ginning structures, wherein power plant space is often at a premium.

Proceeding now with a discussion of the air furnace 90, the latter is conveniently constructed internally closely after the manner of the unit 9 being provided with a lower combustion compartment |00, an intermediate compartment |0| about the tubes or iiues, and an upper compartment |02, which is or may be in connection with chamber 'ISAof the heat exchanger. vllue or tube sheets or the like are shown at |03 in the lower 'portion and |08 in the upper portion of the shell- |05. The combustion takes place in obvious manner as in the chamber |00, the products of combustion passing through the tubes |06, thence into the upper chamber |02 and out through the combined exhaust and iiue stack 85 to atmosphere.

The air circuit through the furnace unit 90 is confined to the chamber 0| between the lue sheets or headers |03, |04, being the space about the tubes |05'. Air delivered to the unit 90, enters the chamber |0| of the unit through the adjoining open ends of the units, the latter providing a common opening indicated at (Figs. 2 and 4). Thus the air circuit through both the tube compartments, is uninterrupted, and the hot air proceeds outwardly from the compartment vequipment proper.

be dispensed with in operation.

It will have appeared that, irrespective o1" whether or not the air furnace is operative, the air stream in traversing the hood 30 is rst raised somewhat in `temperature above the ambient, by direct radiation from the engine 20, which it will be assumed is in operation to drive the shaft I5, theaccessories connected thereto, and the gin After the air stream passes the fan or blower, then traverses the water radiator 23, assuming the engine to be operating at full-load or a substantial proportion of fullload, the air will be further raisedin temperature to an extent depending in great measure upon the outside or ambient temperature, and in perhaps a majority of cases, to a temperature of 150-160 degrees F. representing approximately the optimum temperature range for most efcient drying effect of the cotton. 'I'he air stream, in proceeding through conduits 36 and 4| under propulsion by the fan or blower 40, is conducted through the radiator and into the exhaust heat exchanger 9|, whereupon due to exposure to the hot tubing surfaces in the air circuit of the ex-` changer, it is still further raised in temperature. The air stream thence will traverse the heating chamber or air circuit within the air furnace, and may be still further heated therein through operation of the burner 60, after which the heated stream passes by way of duct 50 into the gin, cotton dryer, or in part or whole, to the air blast nozzles associated with the ginning equipment.

It will have appeared from the foregoing description that the blower 40 in the location shown by Fig. 1, serves as an induced draft fan in impeiling the air through the hood 30 but operates as a blower through the radiator and other portions of the duct system beyond the fan. It is obvious that the blower may be located in other positions than as shown in the'duct system, and in relation to the several items of apparatus; for example, it may be located at or near the inlet 32 or ahead of radiator 23, or even beyond the assembly -9I'.

It is important to note that the system to which the present improved air heater and heat exchanger apparatus is particularly adapted, provides for maintaining the air for cotton drying Vat a substantially constant temperature. i

Obviously the heat emitted by the radiator and exhaust heater, is dependent greatly upon a uctuating condition of engine loading, and is therefore variable. For the purpose of equalizing such occasional variations in engine waste heat, the air heater or furnace lunit 90- is available as a standby unit, for example during a starting or warming up period, or whenever necessary to augment the engine Waste heat to bring the air stream to the minimum temperature necessary for drying purposes, for example, 150-160 cle-` grees. Whenever the heat supplied by the cooling water and exhaust is inadequate to bring the air stream to this temperature, the burner 60 may be operated to make up whatever deficiency may exist. l

It will have appeared that the system as described is exceedingly flexible as to the range of heat supply. Obviously the radiator heat may be used alone, as a sole thermal source for the drying air stream. The next greater stage of heat supply would consist in utilizing engine and radiator heat, together with the exhaust exchanger, and a stili greater supply is obtainable through the use of these elements together with the air furnace or heater.

It will be noted that all of the several heating elements characterizing the present invention are comparatively inexpensive, and may be assembled as a compact unit in the immediate vicinity of the engine, usually within the engine room, so as to be readily accessible to the ginner at all times. Furthermore, the two major wasteheat recovery units, viz., the radiator 2l and exhaust heat exchanger 9|, do not of themselves add any additional elements to the system, the present practice consisting merely, in most instances, of utilizing a. standard radiator inthe duct system to adapt it for the present purpose. Since some form of exhaust pot, muiiler or silencer is almost invariably provided with the engine, these more conventional elements be-` come unnecessary since their function is performed by the present exhaust exchanger which serves eilicientiy as a silencer. Furthermore, the formerly prevailing practice of utilizing a distinct radiator fan is obviated by using the fan or blower 40, serving the dual purpose oi a radiatcr cooling fan and an impelling agency for moving the air through the ducts and units of the system.r

As has been briefly mentioned heretofore, the heating system characterizing the present invention, provides admirablyy for ventilation of the ginning plant. To this e'nd, the radiator may be disposed within the'engine room, as may the exhaust heat exchanger and any other or all of the elements referred to. Since the fan has, in most instances, a capacity of about 5,000 cubic feet per minute, this amount of air is taken by the system from the interior of the plant, is forced through the heating system and discharged to the atmosphere through the dryer or gin. The air intake may be through an open window, door or other opening in the ginning plant structure.

Although the invention has been described by making specicreference to a preferred and inclusive combination and an advantageous arrangement of mechanically and thermally related elements, it will be .understood that numerous changes may be made in the elements, as well as in their arrangement, and further in the utilization oi' numerous sub-,combinations of the items of apparatus disclosed. all without departing from the full intended scope of the invention as defined by the appended claims.

I claim:

1. An air heater assembly providing at least two air heating sections combined to form a unit, said assembly including a casing structure forming an enclosed body for the unit, spaced tube plates located inwardly o! the opposite ends" of the casing .and forming, with the casing, end chambers therein, tubes connecting the spaced tube plates, and opening at their opposite ends into said end chambers, a hot fluid inlet conduit connected into one end chamber of one of said Y air heating sections of the assembly, combustion means in one end chamber of the other of said air heating sections of the assembly. a nue connected to the opposite chamber of the nrst said heating section oi' the assembly, and serving as an outlet duct for spent gases from the ilrst said section, an air inlet connection to the space between the tube plates in the nrst said section, a liquid radiator in said inlet connection, adjacent the first said section, and an air outlet duct directed from the space about the tubes in said other heating section of the assembly, the tubecontaining portions of said air heating sections of the assembly being in substantially open communication with each other, so as to permit a circulation of air therebetween, and from the air inlet connection to the air outlet duct.

2. A n air heater assembly providing` at least two air heating sections combined to form a unit, said assembly including a casing structure forming an enclosing. body for the unit, spaced tube plates located inwardly of the opposite ends of the casing and forming with the casing, end chambers therein, tubes connecting the spaced tube plates. and opening at their opposite ends into said chambers. a hot fluid inlet conduit connected into one end chamber of one of said air heating sections of the assembly, a hot fluid outlet duct directed outwardly of another chamber of said one otsaid air heating sections, combustion means in one end chamber of the other o! said air heating sections of the assembly, coacting with the tubes to pass hot gases to the opposite chamber of the said other heating section oi the assembly, thence into the outlet duct, an air inlet connection to the space between the tube plates and about the tubes in the nrst said air heating section a liquid radiator in said inlet connection, adjacent the ilrst said air heating section, an air outlet duct directed from the space about the tubes in said other heating section of the assembly, the tube-containing portions oi' said air heating sections of the casing being in substantially open communication with each other so as to permit free movement of air from said air inlet duct, to the air outlet duct; the casing structure enclosing the unit, being formed of two companion portions connected to each other along a substantially median plane parallel to the tubes, whereby. when desired, the first said heating section and said other heating sectiony other.

ROBERT D. WILLIAMS. 

